Two members of the family were flown to hospital from the beach.
One person had back injuries and another suffered minor injuries in the ordeal.
Police are investigating how the boat capsized, and were planning to interview the three couple and their son in due course, Mr Aben said.
Contrary to earlier reports, it is unclear whether a large wave caused the boat to flip.
One man died and another remains missing after setting off in a dinghy from near Warkworth on Tuesday.
In as statement released this afternoon, Maritime NZ said the two incidents marked "a tragic beginning to the boating season".
Spokeswoman Sophie Hazulhurst said both of the incidents were under investigation and it had yet to be established what had happened or what were the contributing factors.
"What we do know is that both incidents happened on small boats - around 4m. The vast majority of recreational boating fatalities do occur on boats under 6m. It's simply a fact that you are more vulnerable on small boats.
"The aim of Safer Boating Week is to remind boaties how quickly things can go wrong when out on the water, and to take steps to ensure that you are prepared to deal with whatever happens.
"Those steps include, wearing your lifejacket, taking two forms of reliable communications equipment with you, checking the weather forecast and avoiding alcohol."